Expansion of Product_{k>=1} (1 + x^k)^(sigma_1(k)-k), where sigma_1(k) = sum of divisors of k (A000203).

A319107

Expansion of Product_{k>=1} (1 + x^k)^(sigma_1(k)-k), where sigma_1(k) = sum of divisors of k (A000203).

Terms

    a(0) =1a(1) =0a(2) =1a(3) =1a(4) =3a(5) =2a(6) =9a(7) =5a(8) =17a(9) =17a(10) =38a(11) =33a(12) =88a(13) =75a(14) =169a(15) =181a(16) =343a(17) =353a(18) =712a(19) =728a(20) =1348a(21) =1518a(22) =2591a(23) =2898a(24) =5025a(25) =5615a(26) =9259a(27) =10866a(28) =17160a(29) =20111

External references